Question

Of the 800 seventh grade students and 640 eighth grade students at ​Knox Middle School, 90 students will be chosen at random to attend an ​assembly.
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​Which of the following would be a representative sample of ​the number of seventh and eighth grade students at the school?

Answer 1

Answer:

50 7th grade and 40 8th grade

Step-by-step explanation:

1. add to get total number of students, 1440

2. find percentage of total that are 7th grade students and 8th grade student:

640/1440 = ~45% (are 7th grade)

800/1440 = ~55% (are 8th grade)

3. 55% of 90 is 50, and 45% of 90 is 40